1. Chapter 10.1 Reflection and Refraction

2. Light travels in straight lines through space. Objects like a mirrors can change the path of the light ray to a new straight line.Light travels in straight lines through space. Objects like a mirrors can change the path of the light ray to a new straight line.mirrors Light can change direction to a new straight line by bouncing off a polished surface.Light can change direction to a new straight line by bouncing off a polished surface. We represent the path of light by using straight arrows called rays.We represent the path of light by using straight arrows called rays.

3. The study of light motion by using rays is called ray optics.The study of light motion by using rays is called ray optics. When light rays strike a surface they bounce off and this process is called reflection.When light rays strike a surface they bounce off and this process is called reflection.

4. A light ray reflects from the surface of an object at the same angle at which it strikes the object.A light ray reflects from the surface of an object at the same angle at which it strikes the object.angle The angle of the light is measured from the normal line which is a point parallel to the object.The angle of the light is measured from the normal line which is a point parallel to the object.

5. If a light ray strikes a mirror at 45 degrees, at what angle will it reflect back?If a light ray strikes a mirror at 45 degrees, at what angle will it reflect back? 45 Degrees45 Degrees

6. The angle of incidence is the angle between the incoming light ray and the normal line.The angle of incidence is the angle between the incoming light ray and the normal line.

7. The angle of reflection is the angle between the normal line and the reflected ray.The angle of reflection is the angle between the normal line and the reflected ray.

8. The angle of incidence is always equal to the angle of reflection and this is called the law of reflection.The angle of incidence is always equal to the angle of reflection and this is called the law of reflection.law of reflectionlaw of reflection The incident ray, the normal, and the reflected ray all lie in the same plane and this plane is called the plane of incidence.The incident ray, the normal, and the reflected ray all lie in the same plane and this plane is called the plane of incidence.

9. Highly polished surfaces used to reflect light are called mirrors.Highly polished surfaces used to reflect light are called mirrors. Mirror surfaces of aluminum and silver reflect about 90% of the light that strikes them.Mirror surfaces of aluminum and silver reflect about 90% of the light that strikes them.

10. Most common mirrors are made by putting a thin metal coating on glass.Most common mirrors are made by putting a thin metal coating on glass. If the metal coating is on the first surface that the light hits, the mirror is a first-surface mirror.If the metal coating is on the first surface that the light hits, the mirror is a first-surface mirror. Common household mirrors have the glass in front of the metal coating to provide protection for the thin metal coating. This is called a second- surface mirror.Common household mirrors have the glass in front of the metal coating to provide protection for the thin metal coating. This is called a second- surface mirror.

12. Mirrors with flat surfaces are called plane mirrors.Mirrors with flat surfaces are called plane mirrors. Mirrors with spherical reflecting surfaces are called spherical mirrors.Mirrors with spherical reflecting surfaces are called spherical mirrors.spherical mirrorsspherical mirrors

13. Spherical mirrors can be convex, like the outside of a spoon.Spherical mirrors can be convex, like the outside of a spoon.

14. Spherical mirrors can also be concave, like the inside of a spoon.Spherical mirrors can also be concave, like the inside of a spoon.

15. Convex mirrors provide wide- angle views for security but also make objects appear farther away than they really are.Convex mirrors provide wide- angle views for security but also make objects appear farther away than they really are.

16. Bendable Mirror

17. Reflected light on a convex surface all meet at a focal point in front of the object.Reflected light on a convex surface all meet at a focal point in front of the object.focal point focal point

18. To find the focal point use this equation – focal length = ½ (radius of curvature)To find the focal point use this equation – focal length = ½ (radius of curvature) f = ½ rf = ½ r

19. Find the focal length of a concave mirror with a radius of curvature of 16 cm.Find the focal length of a concave mirror with a radius of curvature of 16 cm. f = ½ rf = ½ r f = ½ (16 cm)f = ½ (16 cm) f = 8 cmf = 8 cm

20. Reflected light on a concave surface all meet at a focal point that appears to be behind the mirror unlike with a convex mirror where the focal point is in front of the mirror.Reflected light on a concave surface all meet at a focal point that appears to be behind the mirror unlike with a convex mirror where the focal point is in front of the mirror. When you view the reflection of an object in a mirror, you see an image.When you view the reflection of an object in a mirror, you see an image.

21. When light strikes an object and reflects, the reflected rays form an image of the object called the virtual image.When light strikes an object and reflects, the reflected rays form an image of the object called the virtual image.virtual imagevirtual image In a convex mirror, since the light rays appear behind the mirror, the image that appears to cause the reflection is called a virtual image since no light rays are actually converging on the image.In a convex mirror, since the light rays appear behind the mirror, the image that appears to cause the reflection is called a virtual image since no light rays are actually converging on the image.

23. When light strikes a different kind of surface such water, some of the light is reflected and some is allowed to pass through. When the light passes through, it changes direction. This change in direction is called refraction.When light strikes a different kind of surface such water, some of the light is reflected and some is allowed to pass through. When the light passes through, it changes direction. This change in direction is called refraction. refraction One common example is when a straw is placed in a glass of water, it looks bent.One common example is when a straw is placed in a glass of water, it looks bent.bent

24. Refraction – Vegetable Oil

25. The speed of light in a vacuum never changes but the speed of light in a transparent medium like water is considerably less.The speed of light in a vacuum never changes but the speed of light in a transparent medium like water is considerably less. The index of refraction is a property of a transparent material defined as the ratio of the speed of light in a vacuum to the speed of light in the material.The index of refraction is a property of a transparent material defined as the ratio of the speed of light in a vacuum to the speed of light in the material.index of refraction index of refraction

26. We use the letter n to represent the index of refraction.We use the letter n to represent the index of refraction. Index of refraction = speed of light in vacuum / speed of light in materialIndex of refraction = speed of light in vacuum / speed of light in material n = c / vn = c / v

27. If the speed of light in a diamond is 124,000,000, what is the index of refraction?If the speed of light in a diamond is 124,000,000, what is the index of refraction? n = c / vn = c / v c = ? What is the speed of light?c = ? What is the speed of light? n = 300,000,000 / 124,000,000n = 300,000,000 / 124,000,000 n = 2.42n = 2.42

28. The light in air that hits another material is called the incident ray.The light in air that hits another material is called the incident ray. The ray that is formed when it is refracted is called the refracted ray.The ray that is formed when it is refracted is called the refracted ray.

29. The angle of refraction is the angle between the refracted ray and the normal.The angle of refraction is the angle between the refracted ray and the normal. Snell’s Law says that as the angle of the incident increases, the angle of the refracted ray increases also.Snell’s Law says that as the angle of the incident increases, the angle of the refracted ray increases also.

30. Refraction Tank

31. Different colors of light are bent slightly more than others. For example, Blue light when passing from air to a glass is bent more than red light.Different colors of light are bent slightly more than others. For example, Blue light when passing from air to a glass is bent more than red light.

32. When the angle of refraction is greater than 90 degrees, a light ray is reflected not refracted. This is called total internal reflection.When the angle of refraction is greater than 90 degrees, a light ray is reflected not refracted. This is called total internal reflection.total internal reflectiontotal internal reflection As the angle of incidence increases, the angle of refraction increases also until it reaches the 90 degrees angle where it reflects. This is called the critical angle.As the angle of incidence increases, the angle of refraction increases also until it reaches the 90 degrees angle where it reflects. This is called the critical angle.

33. Total Internal Reflection Demo

35. A lens is a carefully ground piece of transparent material such as glass.A lens is a carefully ground piece of transparent material such as glass.lens A convex is thicker at the center than it is at the edges.A convex is thicker at the center than it is at the edges. A concave is thinner at the center than at its edges.A concave is thinner at the center than at its edges.